Hello I have the exact same issue, however mine is on pega 7.2. In this version the agent rule does not have the check box"Run on only one node at a time" I had to manually make it run on one node. Still the issue persists.
Can you confirm that the issue is a rule not found exception when running BIX via an agent and provide the specific error you're seeing?
If that is accurate, can you also provide screen shots of the ruleset list where you've added BIX and also the agent configuration? (Be sure to show what parameters are being passed to pxExtractDataWithArgs, along with what class and activity name the agent is running)
Also check that the access group listed on the security tab of the agent rule uses an application that has BIX listed.